If one intends to use a device network that can globally be very far-reaching to the effect that time-critical data of the distributed devices is to be centrally compared and stored, then a uniform time base may be imperative. If these are device-/server systems with servers which are to receive and archive measured-value information and device information with time stamp information from their devices, then this uniform time base may be essential. This may be the case in particular when the devices or clients are to collect information, for example measured-value information, over an extended period of time, and are to forward such information at a suitable point in time block-by-block to the server.
Typically, these days a time server is cyclically contacted for the automatic synchronisation, on an worldwide uniform time base, of computers that have access to the internet. A time server may usually be synchronised by an ultra-precise time-of-day clock or by several other time servers.
For this method to function, each computer that is to use this service should be set up specially for using a time server. This is manually carried out on site at each individual device, and in the case of worldwide distribution of the devices can involve significant work effort with significant potential sources of errors in relation to a uniform time base. If one wishes to make use of this option for control units or field devices from the area of process automation, one realises that personnel putting the devices into operation are often overtaxed with these necessary settings and systems because said personnel simply don't have the necessary know-how. Likewise, this approach is expensive and it cannot be ensured that during ongoing operation operating errors do not occur, which operating errors lead to alteration of the time base or to the set time server no longer being available. Furthermore, over years of operation a time drift can occur in the clocks used, because the time-keeping precision of clocks over time always has technical limitations. Moreover, hitherto-known methods are only to be set as an option; in the case of human error or omission by the setting-up personnel during set-up of the time server, the time information of the measured-value information is not usable and not comparable.